a) Field of the Invention
This invention relates to one light source, and specifically relates to a kind of LED bulb.
b) Description of the Prior Art
LED lighting source is called as “a second lighting technology revolution after Thomas Edison's bulb” due to its high luminous efficiency, full-solid state, and long service life without mercury pollution. Prior art white LED bulb is manufactured by assembling packaged white LED onto a circuit board such that a light source is formed. The main drawbacks of this technology are:
It is difficult to control the phosphor uniformity when applying phosphor powder to a blue LED chip, which leads to the poor brightness uniformity of the finished white LED lighting source, and also it is difficult to adjust the color temperature of white LED lamps after the finished products are formed.
The phosphor directly contacts with the blue LED chip. Heat produced by blue LED chip can result in the high operation temperature of the phosphor, which speed up the aging of the phosphor, and affect the service life of the white LED lamps.
A great deal of organic material is used on pathway of light beam radiation out of the source, such as the lens of organic material, reflector cup of organic material. In the process of long-term use, the color change of organic material will seriously affect the luminous efficiency.
The sealed LED devices can form lots of dazzling light spots in the light source, which fails to suit people's habits. Addition of scattering materials into surface of lighting source partially overcomes dazzling problem caused by point light source. However, this technology will lead to a sharp decline of luminous efficiency of LED bulb and thus affect the promotion of the use of LED light sources.